11,833 research outputs found

    Replacement Paths via Row Minima of Concise Matrices

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    Matrix MM is {\em kk-concise} if the finite entries of each column of MM consist of kk or less intervals of identical numbers. We give an O(n+m)O(n+m)-time algorithm to compute the row minima of any O(1)O(1)-concise n×mn\times m matrix. Our algorithm yields the first O(n+m)O(n+m)-time reductions from the replacement-paths problem on an nn-node mm-edge undirected graph (respectively, directed acyclic graph) to the single-source shortest-paths problem on an O(n)O(n)-node O(m)O(m)-edge undirected graph (respectively, directed acyclic graph). That is, we prove that the replacement-paths problem is no harder than the single-source shortest-paths problem on undirected graphs and directed acyclic graphs. Moreover, our linear-time reductions lead to the first O(n+m)O(n+m)-time algorithms for the replacement-paths problem on the following classes of nn-node mm-edge graphs (1) undirected graphs in the word-RAM model of computation, (2) undirected planar graphs, (3) undirected minor-closed graphs, and (4) directed acyclic graphs.Comment: 23 pages, 1 table, 9 figures, accepted to SIAM Journal on Discrete Mathematic

    Application of Tandem Mass Spectrometry for Analyzing Melamine

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    Modulation Doping near Mott-Insulator Heterojunctions

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    We argue that interesting strongly correlated two-dimensional electron systems can be created by modulation doping near a heterojunction between Mott insulators. Because the dopant atoms are remote from the carrier system, the electronic system will be weakly disordered. We argue that the competition between different ordered states can be engineered by choosing appropriate values for the dopant density and the setback distance of the doping layer. In particular larger setback distances favor two-dimensional antiferromagnetism over ferromagnetism. We estimate some key properties of modulation-doped Mott insulator heterojunctions by combining insights from Hartree-Fock-Theory and Dynamical-Mean-Field-Theory descriptions and discuss potentially attractive material combinations.Comment: 9 pages, 9 figures, submitte

    Unconventional metamagnetic electron states in orbital band systems

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    We extend the study of the Fermi surface instability of the Pomeranchuk type into systems with orbital band structures, which are common features in transition metal oxides. Band hybridization significantly shifts the spectra weight of the Landau interactions from the conventional s-wave channel to unconventional non-s-wave channels, which results in anisotropic (nematic) Fermi surface distortions even with ordinary interactions in solids. The Ginzburg-Landau free energy is constructed by coupling the charge-nematic, spin-nematic and ferromagnetic order parameters together, which shows that nematic electron states can be induced by metamagnetism. The connection between this mechanism to the anisotropic metamagnetc states observed in Sr3_3Ru2_2O7_7 at high magnetic fields is studied in a multi-band Hubbard model with the hybridized quasi-one dimensional dxzd_{xz} and dyzd_{yz}-bands.Comment: 6 pages, published versio

    A TIME SERIOUS ANALYSIS OF THE DYNAMIC INFLUENCE OF FEMALE'S MENSTRUAL CYCLE TO SPORT PERFORMANCE

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    This research uses Cross Correlation Function, C.C.F., as a dynamic relationship evaluation model to study the dynamic influences of the menstrual cycle on sport performances. This research takes females with a regular menstrual cycle to be the test subjects. Their basic body temperatures were recorded every day. A Kistler Quattro Jump force plate was used to record continuously for sixty days the parameters of muscular strength, jump performance, and fatigue index during the subjects performance of a counter-movement Jump (CMJ), squat Jump (SJ), and thirty-second continuous bent leg jumps (CJB). The late stage of the follicular phase and the early stage of the luteal phase have a positive influence on sport performance. This also illustrates that sport performance for female athletes will be varied dynamically in accordance with the time of menstrual cycle

    Angiogenesis and Vasculogenesis at 7-Day of Reperfused Acute Myocardial Infarction

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    Objectives 
This study is to investigate the angiogenesis and vasculogenesis at the first week of reperfused acute myocardial infarction (AMI).
Methods 
16 of mini-swines (20 to 30 Kg) were randomly assigned to the sham-operated group and the AMI group. The acute myocardial infarction and reperfusion model was created and the pig tail catheter was performed to monitor hemodynamics before left anterior descending coronary artery (LAD) occlusion, 90 min of LAD occlusion and 120 min of LAD reperfusion. Pathologic myocardial tissue was collected at 7-day of LAD reperfusion and further assessed by immunochemistry, dual immunochemistry, in-situ hybridization, real-time quantitative polymerase chain reaction and western blot. 
Results 
The infarcted area had higher FLK1 mRNA expression than sham-operated area and the normal area (all P<0.05), and the infarcted and marginal areas showed higher CD146 protein expression than the sham-operated area (all P<0.05), but the microvessel density (CD31 positive expression of microvessels/HP) was not significantly different between the infarcted area and the sham-operated area (8.92±3.05 vs 6.43±1.54) at 7-day of reperfused acute myocardial infarction (P>0.05). 
Conclusions 
FLK1 and CD146 expression significantly increase in the infarcted and marginal areas, and the microvessel density is not significantly different between the infarcted area and the sham-operated area, suggesting that angiogenesis and vasculogenesis in the infarcted area appear to high frequency of increase in 7-day of reperfused myocardial infarction. 
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    Critical Acceptance Factors of Cloud-Based Public Health Records

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    Personal health records (PHR) is a tool that can be used to assist patients in health management, and cloud-based PHR is expected to effectively integrate medical resources and information, elevate overall healthcare quality, and reduce unnecessary medical costs. This study tends to explore the factors that affect users’ intention to use with regard to the Microsoft HealthVault hybrid cloud health system in Taiwan. A research model combined with Unified Theory of Acceptance and Use of Technology (UTAUT) and Task-Technology Fit (TTF) models as well as perceived risks and trust is proposed including 10 hypotheses. After conducting a series survey, in total, 254 valid questionnaires in Taiwan were received. Some preliminary findings are discussed, and it is hoped that this model can be used to explore the key factors influencing usage intent toward the HealthVault
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